Did I do something wrong?

Question
I have a ten gallon freshwater aquarium and I had some gourmi, tiger barbs, and neon tetras in it. Everything was going fine until I noticed that my fish started to die. They weren't just floating on the top of the water like they normally do. Every time a fish died it was because the other fish ate them. Eventually, I only had one gourmi left. Then, about one week later he died also. I don't know what happened, I checked the hardness of the water, I also checked the PH of the water. Everything was perfectly fine. So was the tempurature. I fed them once a day. And if I went on vacation I had someone come over one a day to feed them.

Answer
Hi Tara,
Did you also test ammonia, nitrite and nitrate? A 10 gallon is quite small to house many fish in, Gouramis and Tiger Barbs are known to attack and eat smaller fish and can be quite territorial. One feeding a day is a bit infrequent too. Most fish prefer at least 2 feedings and 3 is ideal rather than 1 large feeding that usually results in food not being eaten to settle and create water quality issues as it decomposes. With the information youve given me about water quality I have to guess, and I would have guess that water quality, aggression or stress caused some deaths and infrequent feedings caused the consumption of the dead. Sorry I cant be more specific. If you have water quality reading besides Ph and hardness, I might be able to offer a little more insight.